Ancient cibilizations established themselves around water sources. While the importance of ample water quantity for drinking and other purposes was apparent to out ancestors, an understanding of drinking water quality was not well know or documented. With regard to drinking water, it took thousands of years for people to recognize that their senses alone were not accurate judeges of water quality.
Methods to improve the taste drinking water were recorded as early as 4000 B.C.Ancient Sankrit and Greek writting recommended water treatment methods such as filtering through charcoal, exposing to sunlight, boiling, and straining. After thousands years, people were gradully a aware of the importance of drinking water in daily life and developed different equipments to qualify our drinking water. Of course we need standars to test whether our drinking water is qualified.
History of drinking water quality standars
The origin of WHO Guidlines for Drinking-Water Quality (GDWQ) goes back to the 1950s. At that time the requirements for safe and potable water supplies became particularly pertinent with the great increase in travel. It became apparent that the reaveler must be provided potable drinking water. The replies to the questionnaire, which was by WHO distributed, clearly indicated the magnitude of the problem and the need for WHO to establish drinking water standards.(WHO 1958)
The 1958 International Standards became to be widely used as a reference in the development of local national standards and as a basis for improved water treatment practices.
Because of the increasing knowledge of the nature and effect of various contaminants, and improved techniques for identifying and determine their concentrations, have led to a demand for further revision of the recommendations. Accordingly the International Standards for Drinking-Water were revised in 1963 and 1971. (WHO 1958, 1963,1971)
The International Standards had been in existence for over a decade until they were superseded by the WHO Guidelines for Drinking-Water Quality( GDWQ ) in 1984.
The second edition of the GDWQ Volume 1 was published in 1983 followed by Volume 2 in 1996 and Volume 3 in 1997. The International Programme on Chemical Safety (IPCS) provided major input to the health risk assessments of chemicals in drinking-water.
In establishing WHO guideline values for chemicals in drinking-water, guideline values were calculated using a tolerable daily intake (TDI) for chemicals showing a threshod for toxic effect. In case of excess lifetime cancer risk was not practical, because of inadequate analytical methodology, a provisional guideline value was set at a practicable level and the estimated associated cancer risk was presented (WHO1993).
A continuing process of updating guideline values was established with a number of chemical substances and mirobiological agents subject to periodic evaluation. Addenda containing these evaluaions were issued in 1998 for Volumes 1 and 2 will be issued as necessary until the third edition of the GDWQ is published approximately 10 years after the second edition (WHO 1998)
Standard
It is known that no one method of filtering or purifying water is going to eliminate 100% of elements from our drinking water. There are guidelines, which measure water standards to make sure our water is safe "Acceptable" contamination levels of water are measured by two standards: maximum contaminant level (MCL) and maximum contaminant level goal (MCLG).
" The goal indicates the level of contaminant at or below which is considered for human consumption. However, given the size of most water systems, today's technological limitations, and the costs involved with water purification, it is impossible to provide the masses with water at or below goal level fro all contaminants. Because of these difficulties, the MCL standard was created as a compromise between public safety and feasibility dictating levels that must be met before water is distributed to the public. This level is usually within 5%of acceptable contaminant rand.
Exmaple:WHO's drinking-water standards 1993
Element/
substance
Symbol/
formula
Normally found in fresh water/surface water/ground water
EPA is the U.S. Environmental Protection Agency's Office of Ground Water and Drinking Water. The federal regulation of drinking water quality began in 1914, when the U.S. Public Health Service set standards of drinking water, an expanded these standards in 1925,1946, and 1962.
Chemical contamination of water supplies was only one of many environmental and health issues that gained the attention of Congress and the public in the early 1970s. A law about drinking water with significant amendments in 1984 and 1996, is administered by the U.S. Environmental Protection Agency's Office of Ground Water and Drinking Water and its partner.
According to several EPA surveys, from 1976 to 1995, the percentage of small and medium community water systems that their water has steadily increased.
Example of EPA's drinking water standards:
Contaminants
MCLG
(mg/L)
MCL
(mg/L)
Potential Health Effects from Ingestion of Water
Sources of Contaminant in Drinking Water
Fluoride
4.0
4.0
Skeletal and dental fluorosis
Natural deposits; fertilizer, aluminum industries; water additive
Volatile Organics
Benzene
zero
0.005
Cancer
Some foods; gas, drugs, pesticides, paint, plastic industries
Carbon Tetrachloride
zero
0.005
Cancer
Solvents and their degradation products
p-Dichlorobenzene
0.075
0.075
Cancer
Room and water deodorants, and "mothballs"
1,2-Dichloroethane
zero
0.005
Cancer
Leaded gasoline, fumigants, paints
1,1-Dichloroethylene
0.007
0.007
Cancer
Plastics, dyes, perfumes, paints
Trichloroethylene
zero
0.005
Cancer
Textiles, adhesives and metal degreasers
1,1,1-Trichloroethane
0.2
0.2
Liver, Nervous system effects
Adhesives, aerosols, textiles, paints, inks, metal degreasers
Vinyl Chloride
zero
0.002
Cancer
May leach from PVC pipe; formed by solvent break down
Coliform and Surface Water Treatment
Conclusion
After thousands years we have our qualified drinking water to drinke. There are several standards of drinking water in the wold. Qualified drinking water is connected to people's health. In the U.S., they have standars of EPA. We also have the standards of WHO.
Maybe even though we don't notice, how important the drinking water standards are, but because of these standards, our daily drinking ware is qualified. We will not worry about our sickness, which drinking water lead to.
But there are some countries still have the problems of drinking water. People are enduring hardships of shortage of water, and shortage of clean drinking water. Anyway it should be a hard project to develop the drinking water standards in the world.
Drinking Water Standards and Developments
Table of Contents
By He Wang
Introduction
Ancient cibilizations established themselves around water sources. While the importance of ample water quantity for drinking and other purposes was apparent to out ancestors, an understanding of drinking water quality was not well know or documented. With regard to drinking water, it took thousands of years for people to recognize that their senses alone were not accurate judeges of water quality.
Methods to improve the taste drinking water were recorded as early as 4000 B.C.Ancient Sankrit and Greek writting recommended water treatment methods such as filtering through charcoal, exposing to sunlight, boiling, and straining. After thousands years, people were gradully a aware of the importance of drinking water in daily life and developed different equipments to qualify our drinking water. Of course we need standars to test whether our drinking water is qualified.
History of drinking water quality standars
The origin of WHO Guidlines for Drinking-Water Quality (GDWQ) goes back to the 1950s. At that time the requirements for safe and potable water supplies became particularly pertinent with the great increase in travel. It became apparent that the reaveler must be provided potable drinking water. The replies to the questionnaire, which was by WHO distributed, clearly indicated the magnitude of the problem and the need for WHO to establish drinking water standards.(WHO 1958)
The 1958 International Standards became to be widely used as a reference in the development of local national standards and as a basis for improved water treatment practices.
Because of the increasing knowledge of the nature and effect of various contaminants, and improved techniques for identifying and determine their concentrations, have led to a demand for further revision of the recommendations. Accordingly the International Standards for Drinking-Water were revised in 1963 and 1971. (WHO 1958, 1963,1971)
The International Standards had been in existence for over a decade until they were superseded by the WHO Guidelines for Drinking-Water Quality( GDWQ ) in 1984.
The second edition of the GDWQ Volume 1 was published in 1983 followed by Volume 2 in 1996 and Volume 3 in 1997. The International Programme on Chemical Safety (IPCS) provided major input to the health risk assessments of chemicals in drinking-water.
In establishing WHO guideline values for chemicals in drinking-water, guideline values were calculated using a tolerable daily intake (TDI) for chemicals showing a threshod for toxic effect. In case of excess lifetime cancer risk was not practical, because of inadequate analytical methodology, a provisional guideline value was set at a practicable level and the estimated associated cancer risk was presented (WHO1993).
A continuing process of updating guideline values was established with a number of chemical substances and mirobiological agents subject to periodic evaluation. Addenda containing these evaluaions were issued in 1998 for Volumes 1 and 2 will be issued as necessary until the third edition of the GDWQ is published approximately 10 years after the second edition (WHO 1998)
Standard
It is known that no one method of filtering or purifying water is going to eliminate 100% of elements from our drinking water. There are guidelines, which measure water standards to make sure our water is safe "Acceptable" contamination levels of water are measured by two standards: maximum contaminant level (MCL) and maximum contaminant level goal (MCLG)." The goal indicates the level of contaminant at or below which is considered for human consumption. However, given the size of most water systems, today's technological limitations, and the costs involved with water purification, it is impossible to provide the masses with water at or below goal level fro all contaminants. Because of these difficulties, the MCL standard was created as a compromise between public safety and feasibility dictating levels that must be met before water is distributed to the public. This level is usually within 5%of acceptable contaminant rand.
Exmaple:WHO's drinking-water standards 1993
substance
formula
Comparison to EPA's standards:
EPA is the U.S. Environmental Protection Agency's Office of Ground Water and Drinking Water. The federal regulation of drinking water quality began in 1914, when the U.S. Public Health Service set standards of drinking water, an expanded these standards in 1925,1946, and 1962.
Chemical contamination of water supplies was only one of many environmental and health issues that gained the attention of Congress and the public in the early 1970s. A law about drinking water with significant amendments in 1984 and 1996, is administered by the U.S. Environmental Protection Agency's Office of Ground Water and Drinking Water and its partner.
According to several EPA surveys, from 1976 to 1995, the percentage of small and medium community water systems that their water has steadily increased.
Example of EPA's drinking water standards:
(mg/L)
(mg/L)
Conclusion
After thousands years we have our qualified drinking water to drinke. There are several standards of drinking water in the wold. Qualified drinking water is connected to people's health. In the U.S., they have standars of EPA. We also have the standards of WHO.Maybe even though we don't notice, how important the drinking water standards are, but because of these standards, our daily drinking ware is qualified. We will not worry about our sickness, which drinking water lead to.
But there are some countries still have the problems of drinking water. People are enduring hardships of shortage of water, and shortage of clean drinking water. Anyway it should be a hard project to develop the drinking water standards in the world.
Resources:
http://www.epa.gov/safewater/consumer/pdf/hist.pdf
http://www.randomhistory.com/1-50/001water.html
http://www.who.int/water_sanitation_health/dwq/arsenicun5.pdf
http://www.lenntech.com/WHO's-drinking-water-standards.htm